The subject matter herein relates generally to electrical cables that provide shielding around signal conductors.
Shielded electrical cables are used in high-speed data transmission applications in which electromagnetic interference (EMI) and/or radio frequency interference (RFI) are concerns. Electrical signals routed through shielded cables may radiate less EMI/RFI emissions to the external environment than electrical signals routed through non-shielded cables. In addition, the electrical signals being transmitted through the shielded cables may be better protected against interference from environmental sources of EMI/RFI than signals through non-shielded cables.
Shielded electrical cables are typically provided with a cable shield formed by a tape wrapped around the conductor assembly. Signal conductors are typically arranged in pairs conveying differential signals. The signal conductors are surrounded by an insulator and the cable shield is wrapped around the insulator. However, where the cable shield overlaps itself, a void is created that is filled with air, which has a different dielectric constant than the material of the insulator and shifts the cable shield farther from the signal conductor. The void affects the electrical performance of the conductors in the electrical cable by changing the dielectric constant of the material near one of the conductors compared to the other of the conductors within the differential pair, leading to electrical skew.
A need remains for an electrical cable that improves signal performance.